Newbie question on pulleys


New Member
Nov 3, 2021
Good day Dear All,

Help needed to sort-out and order the correct pulleys to upgrade the car for AC. Goodwrench engine (no idea what year, 350 cid V8, v-belt drive). Questions as follows:
1. Does the OD (Overall diameter) for crankshaft & power steering (PS) pulleys matter at all? Well, logically it affects v-belt length, but are there any other reasons why different ODs are offered?
2. As crankshaft pulley is to be replaced to 3-groove one & PS one to 2-groove, how important is it to keep original v-belt order, I mean, 1st run for AC compressor via PS pump, 2nd run for PS pump, 3rd run for alternator & water pump. Sorry if my mentioned order is wrong-corresponding manual is not with me at this moment.
3. By the look at current configuration, if water pump and alternator is to be run via 3rd groove, it’s going to be a rather huge misaligment for concerned v-belt. If that’s going to be a case, would any spacers (just to “pull away” alternator and water pump from engine block) will be sufficient to align these 2 parts?

Will appreciate any info/advice, with many thanks in advance.


Veteran Member
Feb 8, 2022
Welcome EK...I have found this forum very helpful over the past few months. I just completed the same task - Vintage Air install on my '70 RS.
- The 3 groove crank pulley I used is from Jegs. 555-504008. Everything lined up fine as follows...
- Inside groove has A/C with outside groove of compressor via water pump.
- Middle groove has P/S with inside groove of pump direct from crank pulley.
- Alternator has outside groove via water pump.

This is with AC on Driver side.

- I purchased the 2 groove power steering pulley from a local NAPA store. Don't recall part number. Be sure to borrow the pulley puller kit.

- The topic of relative pulley size for the water pump is covered in one of the "running hot" threads. It does seem to make a difference according to a few opinions. Certainly, a smaller relative water pulley will make it turn faster . Some feel it cycles the water too fast through the system. I have not looked into how many options there are to fit a larger water pulley. Good luck with your project.


Veteran Member
Feb 8, 2022
Added thought...the 2 groove power steering pulley was the same diameter as the original.

Also...when selecting the crankshaft pulley, you have to know "long" vs."short" water pump. Mine was a long pump. You can slip a good part of your hand between the block and the back of the pump. There are threads on that topic as well.


Staff member
Lifetime Gold Member
Feb 26, 2004
Bloomington, MN
Here's a pic to give you a better idea fo the pulley/belt configuration with A/C.


A/C belt is installed first, but not tightened.
I use an axe handle to hold the PS pump in place to tighten the PS pump hardware. (Crank and PS pump)
Then... tighten the A/C compressor belt. (Crank, PS pulley and A/C compressor pulley)

Lastly, the alternator belt is installed and tightened. (Crank, water pump and alternator pulley)

With the proper brackets and pulleys, you shouldn't need any spacers.

The PS pump pulley has a bit of leeway (in/out on the shaft) for fine tuning the alignment of that one.

Latest posts